1. Field of the Invention
This invention relates to a silicone water-based composition which is useful immediately after mixing as a caulking material.
2. Background Information
Silicone elastomeric emulsions which could be combined with filler to make a product useful as a caulking material were disclosed by Johnson, et al. in U.S. Pat. No. 4,221,688, issued Sept. 9, 1980. Their composition required an aging period after mixing before an elastomeric product was obtained when the water was removed from the emulsion. An improvement in the method of manufacturing such emulsions were disclosed by Elias et al. in U.S. Pat. No. 4,427,811, issued Jan. 24, 1984, in which the filler other than colloidal silica was mixed into the composition after the composition had aged at least two weeks at room temperature. Their method was stated to give improved shelf life of the emulsion. The manufacturing method requires a time of greater than two weeks. The emulsion is an improvement, but the elastomer obtained upon removal of water from the emulsion still shows a lower elongation if the emulsion ages for a period of time before the water is removed.
In order to obtain an elastomer having the properties obtainable when the emulsion is first manufactured, and before a loss in properties due to aging of the emulsion has taken place, it would be necessary to use the emulsion immediately after its manufacture. One method of accomplishing this goal is to store a composition as two or more parts, then make the final mixture at the time of application. This method does not lend itself to the above discussed compositions because they require an aging period between the mixing of the emulsion and the use.
A silicone rubber latex reinforced with silsesquioxanes is taught by Cekada in U.S. Pat. No. 3,355,406, issued Nov. 28, 1967. His curable latex containing an emulsion polymerized hydroxyl endblocked polydiorganosiloxane, silsesquioxane, catalyst, and crosslinker, yielded a rubber when the water was removed. His latexes were used as coatings with a total solids content preferably in the range of 10 to 15 percent by weight. A silicone latex caulk consisting essentially of a siloxane copolymer, filler, aminofunctional alkoxy silane, cationic surfactant, anionic surfactant, and water is disclosed by Butler in U.S. Pat. No. 3,817,894, issued June 18, 1974. He shows the product is stable for at least 7 days under a variety of conditions.
An emulsion which cures upon mixing but is not storage stable is taught by Huebner in U.S. Pat. No. 3,706,695, issued Dec. 19, 1972, which describes a composition useful as an elastomeric electrically conductive coating. The method prepares a composition from an emulsified polydiorganosiloxane, carbon black, organometallic catalyst, and trifunctional silane.